Insulation sheet structure and concrete sandwich wall panel assembly constructed therewith

ABSTRACT

An insulation sheet for concrete sandwich wall panels comprising a sheet base composed substantially of expanded cellular foam and having opposed base surfaces. Protrusions integral with the sheet base extend from each of the base surfaces from a footprint at the base surface to a distal surface away from the base surface. Each of the protrusions has a cross-sectional shape such that a width of the distal surface is greater than a width of the footprint, that is, mushroom-shaped. Narrow ducts extend through the insulation sheet. Optionally, the protrusion distal surfaces are rounded.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISK APPENDIX

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to building construction, more particularly, to pre-cast, insulated, concrete panels.

2. Description of the Related Art

Concrete sandwich wall panels are well known in the building construction art. They typically consist of an insulation layer sandwiched between two concrete layers with ties extending through the insulation layer and into the concrete layers to secure the three layers together. In one method of manufacturing, the first concrete layer is poured in a horizontal form and the insulation is placed on the concrete. Before the concrete sets, the ties are pushed through pre-drilled holes in the insulation and into the concrete. The ties have surface irregularities so that, after the concrete flows around the ties and cures, a secure attachment is provided between the concrete and ties. Finally, the second concrete layer is poured on the insulation. The concrete flows around the surface irregularities of the ties to secure the layers together after the concrete cures.

The above-described method has a number of shortcomings. First, it is very labor intensive because a large number of ties must be individually installed before the bottom concrete layer cures. Second, the purpose of the insulation is to minimize thermal transfer between the concrete layers. In order to minimize thermal transfer, the ties need to be poor heat conductors. However, because the ties support the weight of the concrete, the embedded portions of the ties are steel or other metal alloy, which are very good heat conductors. Consequently, the portion of the ties that reside in the insulation layer needs to be poor conductors. This means that the ties cannot be of a single material, which adds complexity and cost to the manufacturing process. Third, the insulation is composed of extruded polystyrene (XPS), which can only be extruded with a rectangular, board-like cross section, profiled cross sections are not possible. Although XPS is a very good insulator, it does not “breath”, that is, its vapor impermeability is too high, and water vapor can be trapped within the building.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide an insulation sheet for insulated concrete panel assemblies that minimizes construction labor.

Another object is to provide an insulation sheet for insulated concrete panel assemblies that is vapor permeable.

A further object is to provide an insulation sheet for insulated concrete panel assemblies that can be manufactured at or close to the job site.

The present invention is an insulation sheet for concrete sandwich wall panels and comprises a sheet base composed substantially of expanded cellular foam and having opposed base surfaces, and a plurality of protrusions integral with the sheet base and extending from each of the base surfaces from a footprint at the base surface to a distal surface away from said base surface, each of the protrusions having a cross-sectional shape such that a width of the distal surface is greater than a width of the footprint.

A concrete panel employing the insulation sheet of the present invention is made by pouring a first concrete layer into a horizontal form, pushing the insulation sheet into the concrete layer before the concrete sets, and then pouring the second concrete layer onto the insulation sheet.

The insulation sheet of the present invention is composed of an expanded cellular foam (ECF), which can be molded with surface features and is generally vapor permeable. The insulation sheet has a base and protrusions extending from both base surfaces. The protrusions are generally mushroom-shaped so that the concrete flows around and surrounds the protrusions so as to be anchored in the concrete after it sets. The protrusions can be any shape, such as circular and ring-shaped, although any shape or combinations thereof may be employed.

Narrow ducts extend through the insulation sheet to allow air between the first concrete layer and the insulation sheet to escape while pushing the sheet into the concrete and to facilitate vapor permeability of the panel.

So that stacked insulation sheets can slide easily on one another, the surface area of the smallest protrusions is greater than any area of the same shape between protrusions. This means that the protrusions of adjacent stacked sheets will slide on each other rather than falling in between the protrusions. Optionally, in order to facilitate sheets sliding on each other and pushing the sheet into the first concrete layer, the surface of the protrusions are rounded.

Other objects of the present invention will become apparent in light of the following drawings and detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and object of the present invention, reference is made to the accompanying drawings, wherein:

FIG. 1 is a prospective view of a concrete sandwich of the present invention;

FIG. 2 is a perspective view of a section of the insulation panel of the present invention;

FIG. 3 is a top view of a section of the panel of FIG. 2;

FIG. 4 is a cross-sectional view of the panel of FIG. 3 along the line 4-4;

FIG. 5 is a cross-sectional view of the concrete sandwich of FIG. 1; and

FIG. 6 is an enlarged view of a portion of a protrusion.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an insulation sheet for use in concrete sandwich wall panels and a concrete sandwich wall panel assembly that employs the insulation sheet.

A concrete sandwich wall panel 10 of the present invention is shown in FIG. 1. The basic method of making the panel 10 is similar to that of the prior art. The first concrete layer 14 is poured to the desired thickness in a horizontal form. This layer 14 is typically a structural component, that is, it bears the weight of other components. The parameters of the first layer 14 are dependent upon the use to which the panel 10 is being put and the strength needed. As a structural component, the thickness of the first layer 14 will typically be in the range of six to twelve inches. The layer 14 may also include re-enforcement bars as needed according to architectural specifications.

Before the concrete set, the insulation sheet 12 is pushed into the concrete layer 14, as explained below. Then the second concrete layer 16 is poured onto the insulation panel 12 in the desired thickness. The second layer 16 is typically of a lighter weight aggregate about one to six inches thick, again depending upon the use to which the panel 10 is put. Re-enforcement bars and/or wire mesh may be included according to architectural specifications. The concrete layers 14, 16 may be symmetrical, that is, both have the same thickness and composition, or asymmetrical, that is, different thicknesses and/or compositions. The surface finishes of the concrete layers 14, 16 depend on the use to which the panel 10 is put.

The insulation sheet 12 of the present invention is composed of expanded cellular foam (ECF), rather than the extruded polystyrene (XPS) of the prior art. Examples of ECFs are expanded polystyrene (EPS), expanded polypropylene (EPP), expanded polyethylene (EPE), and expanded copolymers such as polystyrene/polyphenylene oxide and modified polyphenylene oxide and polyphenylene ether. The density of the ECF will vary depending upon the application and will typically be in the range of from one to twelve pounds per cubic foot.

ECF is not restricted to a flat shape, as is XPS. ECF can be molded to include surface features. ECF has some vapor permeability so that water vapor is not trapped within the building. In other words, a panel 10 made with the insulation sheet 12 of the present invention “breathes”. Additionally, a “shape-molding” installation is more easily available to a concrete pre-caster, either by in-house investment and in-house production, or by tapping into one of hundreds of local ECF converters that already have ECF manufacturing know-how and an existing ECF infrastructure. Long-term savings would be in either greatly reduced or eliminated costs associated with transporting XPS sheets from one of the relatively few number of suppliers' plants around the country.

The insulation sheet 12 of the present invention has a sheet base 18 and a plurality of protrusions 20 a, 20 b (collectively, 20) extending from the base surfaces 22, 24 of the sheet base 18. The thickness of the base sheet 18 will depend upon how much insulation is desired and can typically be in the range of from one to twelve inches.

As shown in the cross-section of FIG. 4, the width of the distal surface 26 of the protrusion 20 is generally larger than the width of the protrusion footprint 28, the area of the protrusion 20 at the base surface 22. In other words, the protrusion cross-section is generally mushroom-shaped. The idea is that, when the sheet 12 is pushed into unset concrete, the concrete flows around and surrounds the protrusions 20, as at 30 in FIG. 5. When the concrete sets, the protrusions 20 are anchored in the concrete. With protrusions extending from both base surfaces 22, 24, the concrete layers 14, 16 are interlocked via the insulation sheet 12, thereby creating an insulated concrete sandwich. The height of the protrusion 20 and the angle 42 of the protrusion side wall 40 are dependent on the density of the ECF used for the insulation sheet 12 and to the weight and density of the concrete layers 14, 16. Consequently, these parameters will vary according to the application. The protrusions 20 can typically range in height from ½ inch to two inches and the side wall angle 42 can typically range from one to ten degrees.

Because of the integral protrusions, there is no need to manually insert individual ties, like the panels of the prior art. Consequently, manufacturing labor cost is greatly reduced.

FIGS. 2-5 show two different shapes for the protrusions 20: a ring protrusion 20 a and a circular protrusion 20 b. These are merely illustrative shapes and the present invention contemplates that any protrusion shape or combinations of protrusion shapes that have the characteristics described herein may be employed. For example, all the protrusions can be circular or the protrusions can be other shapes, such as squares and rectangles. The size of the protrusions can vary greatly depending upon the application. The ring protrusions 20 a can be, for example, three to ten inches in diameter and the circular protrusions 20 b can be, for example, one to five inches in diameter.

Narrow ducts 32 extend through the insulation sheet 12 at various locations, providing two functions. First, they allow air between the first concrete layer 14 and the insulation sheet 12 to escape while pushing the sheet 12 into the concrete, thereby reducing the possibility of air bubble formation. Second, the ducts 32 facilitate vapor permeability of the final product. The ducts 32 are small enough so that concrete will not fill them. Because a thinner concrete mix would more easily fill larger ducts, the diameter of the ducts 32 is dependent on the viscosity and aggregate mix of the concrete.

Typically, the insulation sheets 12 are stacked for delivery to where the panels are manufactured. It is desirable that, as an insulation sheet 12 is needed for a panel 10, the sheet 12 be easily slid from the top of the stacked sheets 12. Because the XPS insulation sheets of the prior art are flat, they can be slid off quite easily. The insulation sheet of the present invention solves this issue by using protrusions 20 with a smallest distal surface area that is greater than any area of the same shape between distal surfaces 26. For example, in FIG. 3, the smallest protrusion 20 is circular and the distal surface diameter 34 is greater than the largest circular space 36 between distal surfaces 26. This means that the distal surfaces 26 of protrusions 20 of adjacent sheets 12 will slide on each other rather than falling in between the protrusions 20.

If the distal surfaces 26 are flat, slight irregularities in the protrusions 20 may cause the protrusions 20 of adjacent sheets 12 to catch each other when trying to slide one sheet 12 off a stack. To solve this issue, the distal surface 26 of the protrusions 20 are optionally rounded, as in FIG. 4. In the case of the ring protrusions 20 a, the protrusion 20 a has a raised ridge in the center of the distal surface 26 that is rounded to the two edges 36. In the case of the circular protrusions 20 b, the protrusion 20 b is domed. The rounded distal surface 26 facilitates sliding the sheets 12 along each other because the edges 38 of the protrusions 20 will not catch on each other.

Another advantage of the rounded distal surface 26 is that it is easier to push into the first concrete layer 14. The present invention contemplates other shapes for the distal surface, for example, pointed, that facilitate pushing the insulation sheet 12 into the concrete layer 14.

Thus it has been shown and described an insulation sheet and a concrete sandwich assembly constructed therewith that satisfies the objects set forth above.

Since certain changes may be made in the present disclosure without departing from the scope of the present invention, it is intended that all matter described in the foregoing specification and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. 

1. An insulation sheet comprising: (a) a sheet base composed substantially of expanded cellular foam and having opposed base surfaces; (b) a plurality of protrusions integral with said sheet base and extending from each of said base surfaces from a footprint at said base surface to a distal surface away from said base surface; and (c) each of said plurality of protrusions having a cross-sectional shape such that a width of said distal surface is greater than a width of said footprint.
 2. The insulation sheet of claim 1 wherein said distal surfaces have shapes and the smallest of said distal surfaces is larger than the largest area between said distal surfaces.
 3. The insulation sheet of claim 1 wherein said distal surfaces are rounded.
 4. The insulation sheet of claim 1 wherein said sheet includes ducts that extend through said insulation sheet.
 5. The insulation sheet of claim 1 wherein said expanded cellular foam is selected from the group consisting of expanded polystyrene, expanded polypropylene, expanded polyethylene, and expanded copolymers.
 6. An insulation sheet comprising: (a) a sheet base composed substantially of expanded cellular foam and having opposed base surfaces; (b) a plurality of protrusions integral with said sheet base and extending from each of said base surfaces from a footprint at said base surface to a distal surface away from said base surface; (c) each of said plurality of protrusions having a cross-sectional shape such that a width of said distal surface is greater than a width of said footprint; (d) said distal surfaces being rounded and having shapes, the smallest of said distal surfaces being larger than the largest area between said distal surfaces; and (e) said sheet including ducts that extend through said insulation sheet.
 7. The insulation sheet of claim 6 wherein said expanded cellular foam is selected from the group consisting of expanded polystyrene, expanded polypropylene, expanded polyethylene, and expanded copolymers.
 8. A concrete sandwich assembly comprising a first concrete layer, a second concrete layer, and an insulation sheet therebetween, said insulation layer comprising: (a) a sheet base composed substantially of expanded cellular foam and having opposed base surfaces; (b) a plurality of protrusions integral with said sheet base and extending from each of said base surfaces from a footprint at said base surface to a distal surface away from said base surface; and (c) each of said plurality of protrusions having a cross-sectional shape such that a width of said distal surface is greater than a width of said footprint.
 9. The insulation sheet of claim 8 wherein said distal surfaces have shapes and the smallest of said distal surfaces is larger than the largest area between said distal surfaces.
 10. The insulation sheet of claim 8 wherein said distal surfaces are rounded.
 11. The insulation sheet of claim 8 wherein said sheet includes ducts that extend through said insulation sheet.
 12. The insulation sheet of claim 8 wherein said expanded cellular foam is selected from the group consisting of expanded polystyrene, expanded polypropylene, expanded polyethylene, and expanded copolymers.
 13. A concrete sandwich assembly comprising a first concrete layer, a second concrete layer, and an insulation sheet therebetween, said insulation layer comprising: (a) a sheet base composed substantially of expanded cellular foam and having opposed base surfaces; (b) a plurality of protrusions integral with said sheet base and extending from each of said base surfaces from a footprint at said base surface to a distal surface away from said base surface; (c) each of said plurality of protrusions having a cross-sectional shape such that a width of said distal surface is greater than a width of said footprint; (d) said distal surfaces being rounded and having shapes, the smallest of said distal surfaces being larger than the largest area between said distal surfaces; and (e) said sheet including ducts that extend through said insulation sheet.
 14. The insulation sheet of claim 13 wherein said expanded cellular foam is selected from the group consisting of expanded polystyrene, expanded polypropylene, expanded polyethylene, and expanded copolymers.
 15. A method of constructing a concrete sandwich assembly comprising the steps of: (a) providing an insulation sheet comprising a sheet base composed substantially of expanded cellular foam and having opposed base surfaces, a plurality of protrusions integral with said sheet base and extending from each of said base surfaces from a footprint at said base surface to a distal surface away from said base surface, each of said plurality of protrusions having a cross-sectional shape such that a width of said distal surface is greater than a width of said footprint; (b) pouring a first concrete layer into a form; (c) pushing said protrusions of a first of said opposed base surfaces of said insulation sheet into said first concrete layer; and (d) pouring a second concrete layer onto a second of said opposed base surfaces of said insulation sheet.
 16. The method of claim 15 wherein said distal surfaces have shapes and the smallest of said distal surfaces is larger than the largest area between said distal surfaces.
 17. The method of claim 15 wherein said distal surfaces are rounded.
 18. The method of claim 15 wherein said sheet includes ducts that extend through said insulation sheet.
 19. The method of claim 15 wherein said expanded cellular foam is selected from the group consisting of expanded polystyrene, expanded polypropylene, expanded polyethylene, and expanded copolymers. 